Grinding methods



Aug. 4, 19v70 H. w. scHoLlN GRINDING METHODS 2 Sheets-Sheet 1 Original Filed May 3, 1965 /NVENTO/. HAROLD W. SCHUL/N By:-

H. W. SCHOLIN GRINDING METHODS Aug. 4,. 1970 2 Sheets-Sheet 2 Original Filed May :5, 1965 WE/WOR:- HAROLD W SCHOL//V United States Patent Oflce 3,522,678 Patented Aug. 4, 1970 Int. Cl. B24b I 00 U.S. Cl. 'S1-28S 2 Claims ABSTRACT OF THE DISCLOSURE Method of forming a cutting edge at the margin of a circular hole in a sheet metal plate by applying a stream of fluid to the surface of a spherical grinding ball, thereby spinning the grinding ball about a plurality of axes in situ on the plate at the opening.

The present invention relates in general to grinding methods, and has more particular reference to new and improved methods of forming spherical surfaces by grinding procedures, the invention pertaining especially to the formation of a razor blade having a ground cutting edge at and around the periphery of an opening the blade, the present application comprising subject matter divided from my copending application led May 3, 1965, Ser. No. 452,787 now abandoned.

An important object of the invention is to provide methods of grinding spherical surfaces in work pieces; a further object being to provide a cutting edge at the periphery of an opening in a blade element; another object being to provide a razor having a ground cutting edge at and peripherallly of a hole in a razor blade element; a still further object being to provide a method of grinding a spherically domed surface in a workpiece.

Another important object of the invention is to form va shaving edge at the margin of a hole in a razor blade element by grinding the same spherically on one side of the blade.

The foregoing and numerous other important objects, advantages and inherent functions of the invention will be more fully understood from the following description, which, taken in connection with the accompanying drawings, discloses preferred embodiments of the invention.

Referring to the drawings:

FIG. 1 is a side elevation view of a razor embodying the present invention;

FIG. 2 is a top view of the razor shown in FIG. 1;

FIG. 3 is a sectional view taken substantially along the line 3-3 in FIG. 2;

FIG. 4 is a sectional view through a blade element of the sort embodied in the razor shown in FIGS. l, 2 and 3, showing a stream of fluid impinging on the surface of a spherical grinding ball to illustrate a way of grinding a cutting edge in the element;

FIG. 5 is an enlarged sectional view of a portion of the razor shown in FIG. 3

FIG. 6 is a side elevation view of a modified form of razor embodying the present invention.

FIG. 7 is a top plan view of the razor shown in FIG. 6;

FIG. 8 is a sectional view taken substantially along the line `8---8 in FIG. 7;

FIGS. 9 and 11 -are enlarged sectional views respectively taken substantially along the lines 9-9 and 11--11 in FIG. 7; and

FIG. 10 is a greatly enlarged sectional view through the cutting edge portion of blades embodying the present invention.

To illustrate the invention the drawings show razors `11 each comprising a thin sheet metal blade or blades 13y supported in a preferably molded handle 15 of suitable plastic or other readily moldable material. The blade element or elements 13 are each formed with one or more preferably circular holes, openings or perforations 17 therethrough, the margins of said openings being sharpened to form peripheral, inwardly facing iine cutting edges 19 around the holes 17.

As shown more particularly in FIGS. l-S of the draw ings, the razor may comprise a single, spherically curved plate or blade 13 formed with a plurality of spaced holes 17 extending therethrough, said holes being preferably circular and having a diameter of the order of four to five tenths of an inch. -Eminently satisfactory results are realized where the diameter of the openings is precisely 0.437 of an inch, although obviously the openings need not be held precisely to the size mentioned. While the plate 13 may be formed with a single opening, if desired, it is preferable to provide three or more equally spaced openings, preferably arranged circularly about and equally spaced from a central point. As shown, it is convenient to provide a spherically curved blade 13 having a circular marginal edge and provided with four circular openings in equally spaced circular arrangement about the center of `the plate.

In order to manufacture the razor blade, a thin disc of suitable razor blade material, such as carbon steel, tool steel, stainless steel and the like, may rst be blanked to size. It may then be pressed or otherwise shaped to the desired spherical configuration, the radius of the curvature being preferably of the order of two inches. The convex side of the blank may then be ground precisely to form a surface Z0 having the desired radius of curvature. The holes 17 may be pierced, punched or otherwise formed in the disc, after which beveled surfaces 21 may be machined at the edges of the openings 17, on the concave side 23 of the plate 13, and also at its peripheral edge. The blade may then be tempered to obtain desired hardness.

The peripheral edge of the blade may be ground to size, as by rotating the same against a grinding wheel. A ball shaped grinding tool or wheel may be employed to rough-grind the edges of the holes, one at a time, from the inner or concave side of the plate 13. The peripheral edge of the plate then may be lapped to attain a more accurate dimension and a finer finish, after which the surfaces 2.1 may be lapped to form the knife edges 19, lapping being accomplished as by .means of a diamond dust coated or impregnated ball B of brass, bakelite or steel having a diameter preferably of the order of one inch, the ball preferably being spun in lapping position by means of an air jet, applied more or less tangentially, as illustrated in FIG. 4 by the letter A, lapping pressure being applied solely by the gravity weight of the ball.

Finally, the handle 15, which may be made of high impact styrene, nylon or like material, may be applied to the peripheral edges of the blade 13, as by injection molding, said handle, preferably comprising a cylindrical portion 22, having a seat 24 securely receiving the beveled peripheral edge of the plate 13, at one end of said cylindrical portion. The handle also preferably has an outwardly extending llange 25 spaced away from the seat 24. The periphery of the flange `2S may be roughened by diamond knurling the same, as shown at 27, to provide firm finger grippage for the manipulation of the razor.

As shown more particularly in FIGS. 6-11 of the drawings, the razor may comprise a plurality of blade elements 29` each formed with a single hole 17 therethrough, said plates comprising suitable material, such as carbon steel, tool steel or stainless steel. Each blade preferably has squarish peripheral configuration deiined by four straight sides interconnected by arcuate portions at the four corners of the blade. The blades 2.9l preferably are all spherically 3 shaped on the same radius of curvature, which conveniently may be of the order of one inch at the outer or convex side of the elements.

The elements may be formed by first pressing the same to the desired curvature and grinding their convex sides precisely to the desired radius of spherical curvature. Openings 17 may be made in the plates, which preferably are then formed to the desired square shape with arcuate corners. The blade elements may be tempered to provide desired hardness, after which their peripheral edges may be ground precisely to the desired size and shape. A ballshaped tool or wheel may be employed to rough grind the edges of the hole 17' from the rear or concave side 23 of the element to form beveled surfaces 21. The peripheral edges of the plate may then be lapped to final finished condition and the inner beveled surfaces 21 of the hole lapped by means of a diamond coated or impregnated ball, like the ball B, spinning under the influence of an air jet, the gravity weight of the ball only providing lapping pressure. Finally7 the required number of elements 29 may be assembled in a suitable injection molding die and there embedded in the handle 1S comprising suitable moldable material, such as high impact styrene, nylon or like material suitable for injection molding.

It will be seen from the foregoing that the present invention pertains to a new type of razor which may be used for shaving hair from the surface S of any part of the body, and particularly to a novel method of grinding to form the cutting edges thereof. The razor of the present invention is of' unique construction in that it does not require any special type of holder or guard for the blade. The razor is unusual, also, in embodying a spherical blade element having one or more holes marginally ground to a tine, sharp cutting edge around the borders of the hole or holes. When the spherical blade is pressed upon and wiped across the surface to be shaved, the skin protrudes itself slightly into the hole, thereby exposing the hairs for shaving. By applying a circular motion to the razor, a shearing action is produced upon the hairs, because of the mutually inwardly facing character of the shaving edge. Accordingly, a smooth, clean shave may be obtained with a minimum of shaving strokes.

By providing a plurality of relatively small razor edged holes, the possibility of cutting the skin While shaving is minimized, and, indeed, substantially prohibited. The reason why inadvertent cutting of the skin, while shaving, is substantially inhibited, is, first, because the area of skin exposed in the blade opening is relatively small, and, second, because there is no opening disposed centrally in the razor; but the hole or holes are all offset radially from the center of the razor, the several shaving openings being all grouped circularly around the center of the razor. As a consequence, when the razor is held by the rim 27, the cutting action is always of shearing character while the razor gyrates circularly across the surface of the skin being shaved. If a centered hole were to be provided in the razor, it would be possible to rotate the razor about the center of the shaving opening, in which case there would be a tendency to cut a circle of skin without cutting any hair. It is therefore desirable that no shaving opening be centered in the razor.

The number of shaving openings and their relative size may be varied, of course; but it has been experimentally determined that four holes, having a diameter of the order of four to five tenths of an inch, that is to say, /i/l@ of an inch, at the honed cutting edges thereof, and ydisposed about the center of the razor, in the manner shown in FIGS. 2 and 7 of the drawings, appears to be a practical and satisfactory, if not optimum, arrangement.

The unitary spherically curved blade of the razor shown in FIGS. 1-5 is unique in that the cutting edges of the blade are formed by the intersection of two spherical surfaces, so that a sharp cutting edge may be easily ground and lapped or honed, since it is unnecessary to maintain any close tolerance relationship between the outside radius of the blade, which is preferably of the order of two inches, and the spherical radius of the inner inclined sides 21 of the cutting edges, at the several openings, which is of the order of one-half inch, being lapped by the one inch diameter sphere B. These inner inclined sides of the cutting edges are preferably ground and lapped by a ball having a diameter of the order of one inch, as shown more particularly in FIG. 4 of the drawings.

This form of blade has an inherent design limitation in that the angle of incidence of the cutting edges 19 upon the surface S being shaved, which can not be varied, is determined by the curvature of the outer spherical surface of the blade element 13. It has been determined that, under certain circumstances, it is desirable to have a somewhat steeper angle of incidence of the cutting edge with respect tothe surface being shaved, that is to say, an edge that provides more scraping action. This, of course` could `be accomplished by bulging the edges of each hole outwardly, thereby making the grinding of the cutting edge extremely diicult because of the necessity of Working upon the outer surfaces of conically bulged edge portions of the holes.

The razor construction shown in FIGS. 6-10, however, provides cutting edges having a relatively steeper angle of incidence with the surface t0 be shaved than in the FIGS. 1-5 embodiment, the desired result being accomplished by producing separate blade elements each having its own opening and a radius of outer spherical curvature considerably smaller than that of the blade element in the FIGS. 1-5 embodiment, the curvature of the blade elements in the FIGS. 7-10 embodiment being such as to present the cutting edges at a desired relatively steep inclination with respect to the surface to be shaved.

As shown more particularly in FIGS. 9 and 10 of the drawings, each blade 29 of the embodiment shown in FIGS. 6, 7 and 8 may be spherically curved on a radius of the order of one inch, as compared `with the two inch curvature radius of the blade in the FIGS. 1-3 embodiment. The beveled surfaces 21, 21 defining the cutting edge 19 in both embodiments, however, may be formed by lapping with the same one inch diameter ball B.

It is thought that the invention and its numerous attendant advantages Will be fully understood from the foregoing description, and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the forms herein disclosed being preferred embodiments for the purpose of demonstrating the invention.

I claim:

1. The method of forming a cutting edge at the margin of an opening in a plate which comprises spinning a spherical grinding ball in situ on the plate at said opening, by directing a uid stream under pressure against the spherical surface of said ball.

2. The method as set forth in claim 1, wherein the fluid stream is an air jet and is applied to the surface of the ball angularly and off center whereby the ball is rotated about numerous different axes.

References Cited -UNITED STATES PATENTS 525,441 9/ 1894 Bruner 51-27 1,131,611 3/1915 Newman et al. 51-27 2,119,021 5/1938 Moskovics et al. 304-435 X 2,182,067 12/ 1939 Bruecker 76-104 2,614,321 10/1952 Ackerman 30-49 X LESTER M. SWINGLE, Primary Examiner 

